Engine starter



Dec. 28, 1937.

J. A. CHARTER ENGINE STARTER Filed Dec. 51, 1936 Patented Dec. 28, 1937UNITED STATES PATENT OFFICE ENGINE STARTER Illinois Application December31, 1936, Serial No. 118,535

11 Claims.

The present invention relates generally to engine starters and moreparticularly to springs for use in starters wherein the spring forms ayieldable driving connection and operatively functions to cause movementof a pinion or driving member.

The present invention concerns the general type of engine starterswherein a coiled spring structure is coupled with a pinion adapted to bemoved into and out of engagement with a driven gear of the engine ormotor, the spring structure cooperating with a projecting member,sometimes referred to as a tracker, which is movable between theconvolutions of the spring 1 structure, in which device the tracker, inresponse to rotation of the starting motor, automaticallymoves thepinion into operative position to drive the engine.

In the present type of starter the energy to drive the engine is thustransmitted from the tracker to the end of the spring and resilientlytherethrough to the pinion. Normally the spring is secured in somemeasure to the pinion at one end thereof, the assembly being relativelyfree to move axially, and the other end of the spring being free exceptwhen it resides against the tracker in driving position and the pinionis in mesh with the motor gear.

It is, moreover, important that the interior diameter of the spring beof greater dimension than any interior axial support for the spring orpinion since the resilience of the spring necessitates clearance forradial contraction. Furthermore the spring connection with the pinion isprimarily for the purpose of transmitting power thereto andconventionally takes a form adapted to ready replacement rather thanpositive and rigid support of the spring. It is thus apparent that, in astructure of the instant type, the spring is subject to vibration orrattling and general dislocation from its preferred axial position.

It is a purpose of the present invention, therefore, to provide astructure wherein the spring will be more or less positively and rigidlymaintained in a preferred axial position with respect to the starter andwhich will be maintained against normal rattling, vibration ordisplacing forces.

Another object of this invention is to provide an engine starter springstructure which will enhance the wrapping clutch action adjacent theedges of the spring when employed in conjunction with a central driveshaft unit.

Numerous other objects and advantages will be apparent from aconsideration of the following specification anddrawing which disclosesa few devices constructed in accordance with the principles of thepresent invention and in which- Figure 1 is an elevational view of astarter constructed in accordance with the present inven- 5 tion,portions being shown in section;

Figure 2 is a perspective view of a starter, as shown in Figure 1;

Figure 3 is an end elevation taken from the righthand end, as viewed inFigure 1; 10

Figure 4 is an end elevation taken from the lefthand end, as viewed inFigure l; and

Figure 5 is a sectional elevation taken through an alternative preferredform of spring.

Referring now to the drawing more in detail wherein like numerals havebeen employed to designate numerous parts throughout the variousfigures, it will be seen thatin Figures 1 to 4 inclusive there isdisclosed a preferredembodiment of the invention, a starter mechanism'20,

being disclosed in these figures bythe numeral It] and a rotary drivingstructure designated generally by the numeral !2.- The rotary drivingstructure comprises a driven pinion l4 and a sleeve or drum IB- formedintegrally with the pinion. This structure is mounted for rotation upona motor shaft 18 which connects with any suitable starting motor,preferably an electric starting motor (not shown) of the type employedto start gasoline engines or the like. 30"- A driving spring structure20 comprising multiple or double strand convolution for coupling withthe sleeve section-J6 through the agency of hook portions 22diametrically positioned, is provided at free extremities of'the springstrands. These 35' drive shaft l8 mentioned above, a sleeve section 30which is driven by the motor shaft I8 through the agency of a suitablekey and key-way (not 50 shown).

The spring, shown for illustrative purposes, 7 includes a continuousstrand of wire of relatively flat continuous material having a generallycylindrical configuration. The loop end 32,'form- 55- 7 ing oneextremity of the coil, is free from any positive securement to thesleeve 30, the two strands extending helically therefrom in paralleldirections. The axial spacing of the strands forms a helical track orway 34 adapted to be engaged by a suitable tracking member for shiftingthe spring and the pinion longitudinally for causing rotation thereof.At a point midway of the axis of the spring the spacing of theconvolutions is diminished with the result that the strands resideclosely adjacent each other, as indicated at 36 in Figure 1. The freeextremities of the two strands do not terminate at the same point butform the hooks 22 at diametrically opposite points. Thus, the strand,which at the hook end of the structure constitutes the inner strand,continues helically and circumferentially beyond the free extremity ofthe outer strand to present a second diametrically positioned hook orcoupling means. The cylindrical spring coil 20 has an inside diametergreater than the diameter of the sleeve 30 with the re sult that thespring is spaced radially from the outer surface of the sleeve. It willbe obvious that such clearance is practically essential in the operationof the device since it permits further coiling or expansion of thespring.

Referring particularly to Figures 3 and i, how ever, it will be noticedthat the strands at both extremities are deformed inwardly to a pointadjacent the sleeve. Referring to the hook end of the spring, as shownin Figure 3, the two strands are deformed relatively sharply invhrd- 1y,as shown at 38, from the normal inside radius of the coil, as indicatedat 4|). The opposite extremity of the coil, namely, the loop end 32, issimilarly offset radially inwardly of the interior of the coil, asindicated at 42 in Figure 4. In the instant embodiment the inwarddeformations of the coil occur in a relatively short arc, therebypermitting efiective resilient spring action along substantially theentire length of the convolutions. Thus, in the preferred embodimentshown in Figures 1 to 4, the entire extent of each inwardly deformedportion of the spring constitutes less than degrees: of a convolution.If substantial portions of the spring were deformed inwardly and incontact with the sleeve 36, contraction or stretching of the springalong this area would be hindered.

In use the spring occupies a position, such as that shown in Figure 1,the normal inner cylindrical face of the spring 40 being oifset from thesurface of the sleeve 30 but being unsupported thereby and free tooperate. The end portions 38 and 42, however, being deformed inwardly,will contact the surface of the sleeve or reside closely adjacentthereto. The sleeve 36 is provided with a radial projection, abutmentmember or tracker 44 which is secured to or formed integrally therewithand positioned between the convolutions of the spring, as shown inFigure 1.

In operation the motor shaft 4!] is initially energized under theinfluence of the starting motor, rotating the sleeve 31] in a clockwisedirection, as viewed from the right end in Figure 1, forcing the pinionaxially into mesh with the flywheel gear (not shown) on the motor. Thetracker having ultimately reached the loop 32, will continue to revolve,driving the spring 26, the sleeve [6 and the pinion resiliently inaccordance therewith. When the motor has commenced to operate under itsown power it will operate the flywheel gear, which is much larger thanthe pinion I4, at a peripheral speed greater than that of the pinion,thereby rotating the rotary driving structure l2 in a clockwisedirection with respect to the sleeve 30. Thus, the tracker 34 moves inthe way 44 to a position shown in Figure 1, retracting the pinion I4.During operation of this device, however, the spring will remaingenerally centered in a predetermined position with respect to theremainder of the assembly due to the inwardly projecting portions 38 and40 which tend to support and space it with respect to the sleeve. Thisfunction will take place at all times whether the starter is beingemployed to initiate operation of the motor or is merely in idleretracted position.

The alternative preferred embodiment shown in Figure 5 comprises adouble stranded spring having hooks 22 thereon and a spaced trackportion 34, as well as an area 36 where the strands are positionedrelatively close to one another. According to this embodiment, however,the spring, instead of being wound in generally helical form to providea substantially cylindrical appearance, is made originally with an innerconfiguration whereby the interior edges of the strands are situatedalong a curve 4G of arcuate form. The interior configuration of thespring is, therefore, generally concave while the exterior is convex,or, taken as a whole, barrelshaped. :When employed in conjunction with astarter organization, such as shown in Figure 1, the terminal portionsof the spring, being formed along arcs of substantially the same radii,will reside adjacent the sleeveSll or in contact therewith, as definedheretofore. The intermediate convolutions of the spring 20, however, dueto their concave positioning will be spaced from the surface of thesleeve 30 and will operate in the normal manner to resiliently transmitenergy to the pinion l4, as well as to guide the tracker 44.

It will be apparent that structures of the instant type normally aresupported only at the hook end due to their axial clearance, being freeto vibrate and wobble because of the spacing from the sleeve 30 and thelack of any positive connection other than that of the hook ends 22 withthe slots 24. Moreover, for convenience in assembly and operation, thehook ends 22 are primarily designed to transmit energy circumferentiallythereof and not to form a rigid sole support for the coil 20. As aresult the coil tends in most conventional structures to be ratherloosely situated. Consequently, this unit is subject to considerablerattling or clashing under the influence of displacing or vibratoryforces.

According to the present invention, however, this defect is remedied andthe spring relatively positively situated against transverse movementwith respect to the sleeve 30. In addition, this effect results in amore unitary assembly since the spring is continually maintained inpreferred operative position.

In addition the present structure tends to enhance the wrapping clutchaction, that is, at the moment the starting motor begins to transmit ahigh degree of torque through the assembly to the flywheel gear or thelike, the spring tends to contract axially. As a result, the endportions, which are adjacent or already in contact with the centralsleeve, tend to further wrap down upon the sleeve and grasp the surfacethereof. This wrapping action at the edge causes suificient engagementwith the surface of the sleeve to transmit a large portion of the energyfrom the ends of the spring to the sleeve, consequently BOT distributingthe forces at the end. It will be apparent that the present structureimproves this known action by causing increasing clutching or wrappingaction at and adjacent the points where the extremities of the springcontact the sleeve.

The length of the way 34 is suificient to permit the desired axialmovement of the spring and pinion with respect to the sleeve 30 andterminates intermediate of its ends at the predetermined limit of thesaid track. The axially adjacent convolutions 36 of the spring, asviewed to the right in Figure 1, permit limited tensioning, becomingrelatively rigid when the convolutions have been tensioned to a pointwherein they closely approach each other. The axially spacedapartconvolutions, as viewed to the left in Figure 1, permit resilient actionbeyond this point. In use, therefore, at the point where the resiliencyof the convolutions is lowest, the entire spring, while remaining tosome degree resilient, involves a sharply increased factor to ultimatelycushion the stresses.

It is thought that the invention and numerous of its attendantadvantages will be understood from the foregoing description and it isobvious that numerous changes may be made in the form,

\ construction and arrangement of the several parts without departingfrom the spirit or scope of the invention, or sacrificing any of itsattendant advantages, the form herein described being a preferredembodiment for the purpose of illustrating the invention.

The invention is hereby claimed as follows:

1. An engine starter of the type in which a pinion and a spring coupledtherewith move together as a unit, said spring including a double coilof spring wire forming a series of convolutions, a portion of theconvolutions at least being spaced to provide a helical way, meanstraversing said helical way toward one extremity of said coiled spring,providing an abutment surface adapted to be engaged for drivingpurposes, coupling means provided at the free extremity of each strandat the opposite end of said coiled spring for coupling with said pinion,and a drive shaft unit centrally of the spring, the convolutions beingnormally spaced therefrom, a portion at least of said convolutions beingbent inwardly to contact said drive unit whereby to position said springwith respect to the drive unit.

2. An engine starter of the type in which a pinion and a spring coupledtherewith move together as a unit, said spring including a double coilof spring wire forming a series of convolutions, a portion of theconvolutions at least being spaced to provide a helical way, meanstraversing said helical way toward one extremity of said coiled spring,providing an abutment surface adapted to be engaged for drivingpurposes, coupling means provided at the free extremity of each strandat the opposite end of said coiled spring for coupling with said pinion,and a drive shaft unit centrally of the spring, the convolutions beingnormally spaced therefrom, portions of the spring being bent inwardly atthe extremities to contact said drive shaft unit whereby to positionsaid spring with respect to the drive shaft unit against radialdisplacement.

3. An engine starter of the type in which a pinion and a spring coupledtherewith move together as a unit on a central axially disposed driveshaft unit, said spring including a series of convolutions of springwire, a portion of the convolutions at least being spaced to provide ahelical way, means traversing said helical way toward one extremity ofsaid coiled spring, providing an abutment surface adapted to be engagedfor driving purposes, and a coupling means provided at the otherextremity of said spring for coupling with said pinion for transmittingenergy thereto, a portion of said convolutions of the spring beingnormally spaced radiallyv outwardly of said drive shaft unit, theextremities of said coil being bent inwardly to a point adjacent saiddrive shaft unit whereby to position said spring against rattling orlateral displacement.

4. In an engine starter in which a pinion and a spring coupled therewithmove together as a unit, a central drive shaft unit, said spring beingmounted loosely over said drive shaft unit and coupled adjacent one endthereof to the pinion, the other end of said spring being free frompositive attachment, a portion of the convolu tions adjacent said endbeing offset inwardly whereby to contact said drive shaft unit andsupport the spring against unauthorized lateral displacement orvibration.

5. In an engine starting device, a cylindrical driven member, a pinionmounted for rotational and axial movement with respect thereto, and aspring operatively connected to said pinion at one end and encirclingsaid cylindrical driven member but spaced radially therefrom, the otherend of said spring being free, at least a portion of said spring beingoffset inwardly toa point adjacent said cylindrical driven memberwhereby to position said spring laterally.

6. In an engine starting device, a cylindrical driven member, a pinionmounted for rotational and axial movement with respect to saidcylindrical driven member, a spring operatively connected to said pinionand encircling said cylindrical driven member but spaced radiallytherefrom, the convolutions of said spring being spaced to provide ahelical track over a portion thereof, and a tracking member secured tosaid cylindrical driven member and engaged in said track, portions ofsaid spring adjacent the ends being offset inwardly to positionsadjacent the cylindrical driven member whereby to position said springradially and inhibit unauthorized displacement thereof.

7. A coiled spring for forming a driving connection in an enginestarter, said spring comprising a double strand of coiled spring wire,the convolutions of said double strand being axially spaced to provide ahelical way whereby to accommodate and guide an abutment member, thestrands being joined together at one extremity to form a central loop,the opposite ends of said strands having means thereon to transmitenergy to a pinion, the extremities of said spring member being offsetinwardly and radially.

8. A coiled spring for forming a driving connection in an enginestarter, said spring comprising a double strand of coiled spring wire,the convolutions of said double strand being axially spaced to provide ahelical way whereby to accommodate and guide an abutment member, the

strands being joined together at one extremity to form a central loop,the opposite ends of said strands having means thereon to transmitenergy to a pinion, the coil beingof generally cylindrical configurationand the end portions thereof being deformed inwardly in a relativelysharp curve whereby to position said coil with respect to a centralspindle or the like. i

9. A coiled spring for forming a driving connection in an enginestarter,said spring comprising a double strand of coiled spring wire, theconvolutions of said double strand being axially spaced to provide ahelical way whereby to acoommodate and guide an abutment member, thestrands being joined together at one extremity to form a central loop,the opposite ends of said strands having means thereon to transmitenergy to a pinion, the coil being of generally barrel-shapedconfiguration and the end portions thereof being deformed inwardly in arelatively sharp curve whereby to position said coil with respect to acentral spindle or the like.

10. In an engine starting device, a drive shaft unit, an engine drivingmember on said unit for both longitudinal and rotary movement, saidmember being adapted in one shifted position to operatively engage anengine part to be driven, a coiled spring structure on said unit spacedradially therefrom and connected at one extremity with the enginedriving member, said spring structure including a double strand ofspring wire forming a helical way, and means rotatable with the unit andpositioned between the double strand convolutions of said springstructure for controlling the longitudinal shifting of said springstructure and engine driving member, portions of said spring beingoffset inwardly to contact said drive shaft unit whereby to support saidspring.

11. In an engine starting device, a drive shaft unit, a pinion mountedfor rotational and axial movement with respect to said drive shaft unit,and a spring surrounding at least a portion of said unit providing ayieldable driving connection between said drive shaft unit and saidpinion, one extremity of said spring having a coupling in the form of anopen ended hook, the

- opposite extremity of said spring being free and offset inwardly to apoint adjacent said drive shaft unit whereby to position theintermediate portion of said spring laterally with respect to said unit.

JAMES A. CHARTER.

